"Take the opposite wall from the source of light — whether it be a door or a window — and mirror the entire thing in three vertical sections. The middle section should constitute 50% of the wall, and the two side panels should be 25% each. It's an elegant look, and it always doubles the room visually. In truly tiny spaces, like my guest bathroom, I mirrored every square inch where there should have been paint, except the ceiling." —ANN DUPUY, NEW ORLEANS, LA

"Instead of painting walls bright white to make the space feel larger, take the counterintuitive approach — go deep, dark, and mysterious. A teal blue silk wall covering or an entire wall of leather floor tiles gives you a striking look without taking up any floor space." —FRANK ROOP, BOSTON, MA

"Take the focus off the architecture and beam it on an astonishing object — it can be anything from a specimen plant to a Da Vinci cartoon to a nude portrait." —THOMAS JAYNE, NEW YORK, NY

"In a narrow kitchen, have as few upper cabinets as possible. Get rid of stuff. Choose one set of dishes for all occasions, one sauté pan, and one set of glasses — those stemless wineglasses work for juice, cocktails, wine, milk. Live only with what you love and use daily. Think of it as a different kind of abundance." —CLARE DONOHUE, BROOKLYN, NY

"Gather a fabulous, motley collection of mirrors — antique, new, vintage, French, Italian. Starting with one large mirror in the center, arrange a grouping on one wall. It's the one instance where more is more." —STEPHEN SHUBEL, SAN FRANCISCO, CA

"Do the whole room in the same fabric, and I do mean everything — walls, curtains, upholstery, even the lampshades and picture frames, whether it's a leopard print or a toile. One wild print all over the place enlarges a small space, makes it feel cohesive, and adds a big wow factor." —AMANDA NISBET, NEW YORK, NY

"Accentuate the intimacy. If it were a tiny entryway, I'd use patterned wallpaper and a hanging fixture with a subtle, diffuse light source. I'd add a frameless mirror flanked by reflective sconces, both hung a little on the low side, and then I'd make a composition of small-scale paintings and pictures, placing them unpredictably and irregularly to engage more playfully with scale." —SARA BENGUR, NEW YORK, NY

"Panel a small room in paint-grade raised or recessed paneling, using tone-on-tone light colors to keep it airy. And if the room doesn't already have a fireplace, I might add a wonderful mantelpiece for warmth and depth — but it would have to look like a truly functional fireplace!" —CHRISTOPHER MAYA, NEW YORK, NY

"I once worked wonders in a creepy basement by detailing it with built-in beds, columns, pilasters, and crown moldings painted in gentle, soft colors. Such details communicate largesse, and they fool the eye by adding height." —MARY DOUGLAS DRYSDALE, WASHINGTON, DC

"Go straight to fantasyland. I'm thinking of trellis-covered walls, high-gloss lacquer ceilings, and graphic painted floors. While I was at Parish-Hadley, I had a chance to study pictures of all those low-ceilinged country rooms Mr. Hadley and Mrs. Parish pulled off in Maine in the 1960s — mind-boggling charm and shockingly innovative!" —PATRICK KILLIAN, PALM BEACH, FL

"Go ahead, use a massive four-poster bed in a tiny bedroom. As long as there's room for an end table, it actually makes the room look bigger." —MARSHALL WATSON, NEW YORK

"Cover the walls in one of those great new woven wallpapers by Xorel or Carnegie — they come in dozens upon dozens of plain solid colors, but each with a little bit of shimmer to bounce the light around." —HEIDI BONESTEEL, PACIFIC PALISADES, CA

"Saturate the space in one medium or dark color, such as moss, warm dark gray, or chocolate brown. Use it on every door, every ceiling, the trim, the window frames and the door frames, as if you're dipping the whole room in a bucket of paint. It takes away all the boundaries and you're left with the infinity of the universe. It's like Houdini came in and decorated." —BARRY DIXON, WARRENTON, VA

"We have a wonderful old place in Connecticut where the previous owner had taken an odd space between the eaves and put in a skylight and a claw-footed tub, and then covered the walls with white towels! Quirky, sure, but very cozy." —KARI MCCABE, NEW YORK, NY

"Stay with a monochromatic palette of very light-colored wall, floors, and window treatments. The paint color should be an atmospheric neutral such as Farrow & Ball's Shaded White. You could do sisal or sea grass matting or a rug in a similar tone as the walls." —SHARONE EINHORN + HONEY WOLTERS, RUBY BEETS, SAG HARBOR, NY

"Do something over-scale and daring. In a small powder room, I used a large-scale David Hicks wallpaper with Chinese urns all over it. Paradoxically, it helped the room feel bigger. But it can't be a small, busy pattern. It has to be an open, graphic pattern that breathes, with space between the repeats." —KIM ALEXANDRIUK, SANTA MONICA, CA

"One of my favorite small rooms was a dining room at L'Hotel in Paris. You went down a stone spiral stair into this tiny arched vaulted room with one wonderful large table and big plushy chairs. It taught me two things: You can have more fun in a small dining room than a large one, and you can put big pieces in small rooms — just not many of them." —JOHN OETGEN, ATLANTA, GA

"Create a pampering little jewel box, like the cabinet-size rooms of the Gritti Palace in Venice. Do upholstered walls, silver- or gold-leafing on the ceiling or bedposts, upholstery in silk velvet. At $300 a yard, Fortuny fabric is a splurge, but you could do a pair of lampshades and get a lot of bang for your buck." —MALCOLM JAMES KUTNER, NEW YORK, NY, AND KEY WEST, FL